josephv,
That was a very good reference. I especially like the quote
As the 21st century began, experts continued to think of new subtleties in the physics of clouds which might significantly affect the models' predictions.(103) Struggling with the swarm of technical controversies, experts could not even say whether cloud feedbacks would tend to hold back global warming, or hasten it. ... There were also undeniable problems in the basic physical data that the models relied on, and uncertainties in the way the data were manipulated to fit things together. The models still needed special adjustments to get plausible ice ages. And when modelers tried to simulate the climate of the Cretaceous epoch — a super-greenhouse period a hundred millions years ago that had been far warmer than the present and with a CO2 level several times higher — the results were far from the climate pattern geologists reported.
This discussion reminds me of a Newsweek (I think) article I say in the 1970's. Some legitimate scientist deterimed that the friction between the atmosphere and the edge of space (whatever that really means) was actually slowing the rotational velocity of the earth by a measurable amount (pico seconds per century or some such). He presented his findings as a triumph of improvements in instrumentation to be able to detect the slowing.
The popular media got ahold of that and wrote articles that included artist renderings of the earth stopping and everyone flying off.
This discussion never got the leverage that Global Warming has gotten, but there was a lot of real fear that the earth would stop spinning and somehow that would throw everyone off (there was never a clarification about why removing a force that was trying to throw us off the earth would throw us off, but oh well).
This article was very specific that the author feels that computer models "prove" that man's actions are the primary cause of a global temperature increase, melting glaciers, sea level rising, huricanes, tsunamis, and tornados. At the end of the day computer models can't prove anything. Ever. If you start with accurate measurements of all relevant parameters, then models can be helpful in understanding a range of possible outcomes.
We are at a point where the scientific discussion is centering around what is the list of appropriate parameters to measure and what is the technique that researchers should use to conduct these measurements.
The discussion in the popular media is focused on solutions to a problem that we do not have a clear understanding of the relevant parameters, let alone conclusive measuremnts of those parameters.
I don't know if the global temperature is on an increasing or decreasing pattern (right now, at my house I'd say definately decreasing), I'll tell you in a hundred years what the trend was in 2006. I do know that global temperature is a concept that is determined by a very large number of local variables, and local climates. What I'm unwilling to take on faith is that mankind's puny introduction of certain gases is having a driving effect on the global system.
David
